Classic French Onion Soup

Discover how to prepare traditional French onion soup like a chef at a restaurant! This tasty soup, which is made with caramelized onions, a thick savory broth, and toasted cheesy bread, is really simple to prepare, reasonably priced, and superior to any store-bought version available. Gluten-free and vegetarian options are both flexible. It can be prepared without sherry or wine.

I’ve been preparing classic French onion soup in restaurants for many years, and now I’m finally releasing my recipe and detailed instructions on how to make it like a restaurant chef! This tasty soup, which is made with caramelized onions, a thick savory broth, and toasted cheesy bread, is really simple to prepare, reasonably priced, and superior to any store-bought version available.

Why this Easy French Onion Soup Recipe Works?

The rich flavor of this traditional French soup comes from the combination of high-quality beef broth and sweet caramelized onions. We cook the onions slowly to break down their intensity and release their natural sugars, which produces amazing results. The soup gains a depth of flavor from the sweetness of the soft, caramelized onions that can’t be achieved in any other way.

Ingredients For French Onion Soup

4 tablespoons butter (unsalted or salted)
3 pounds onions (see notes) peeled, halved and thinly sliced (about ⅛-thick) yellow onions or sweet Vidalia onions work best
1 tablespoon olive oil or vegetable oil
¼ teaspoon freshly ground black pepper plus more to taste
¾ teaspoon Kosher or sea salt plus more to taste
1 tablespoon dry sherry (replace with cider vinegar if preferred)
3/4 cup dry white wine (replace with broth if preferred)
8 cups beef broth or beef stock
2 tablespoons all-purpose flour
2 fresh thyme sprigs or ½ teaspoon dried thyme
1 bay leaf
1 small baguette sliced ½-inch thick
6 ounces Gruyère cheese, grated (about 1 ½ cups) (replace with Fontina or Mozzarella)
½ teaspoon Worcestershire sauce
Optional: Garnish with fresh thyme leaves or chopped chives.

Instructions For French Onion Soup

Heat the oil and butter in a big pot or Dutch oven over medium heat. Add the onions, salt, and black pepper after the butter has melted. Stir.
Cook, uncovered, stirring periodically, for 45 to 55 minutes, or until the onions are deep golden brown and caramelized. The amount of heat and the size and type of pot you are using will affect the time. You might need to stir more frequently in the middle of cooking. Reduce the heat as necessary if the onions are browning too quickly. Use a wooden spoon to scrape the bottom of the saucepan if the onions are adhering to it. If necessary, add roughly a tablespoon of water to the saucepan and scrape the bottom to deglaze it. This will assist in releasing the jammed parts. Keep cooking.
Add the dry sherry and wine after the onions are golden brown and caramelized. Bring to a boil after increasing the heat to medium-high. Cook for 5 to 6 minutes, or until nearly all of the liquid has evaporated. Stir continuously for approximately one minute after adding the flour.
Add a cup of broth gradually, stirring all the time. Add the worcestershire sauce, bay leaf, thyme, and the remaining broth and stir. After bringing to a boil, lower the heat and simmer for twenty minutes.
Preheat the oven to 400ºF while the soup is simmering. Position the oven rack in the center. Arrange the bread pieces in a single layer on a sheet pan and bake for 8 to 10 minutes, or until the bread is golden and crisp on the edges.
Remove the bay leaf and thyme sprig from the soup when it has finished cooking. According to the chef’s notes, taste and adjust the seasoning.
Place an oven rack about 6 inches below the heat source to broil the cheese topping. Switch the broiler on, either low or high.
Place individual casseroles or ovenproof soup bowls on a baking sheet. Spoon the hot soup into each bowl.Place 1-2 slices of bread on top, depending on size. Make sure there is no overlap in the bread. Add a hefty amount of Gruyere cheese on top.
Melt the cheese and begin to brown the edges by broiling it. Because the broiler browns food quickly, keep a close eye on it.
Top the toasted bread with cheese and broil until melted and bubbling if you don’t have any ovenproof soup bowls. Place a few cheese toasts on top of each soup bowl.

Make Ahead, Storing, Freezing and Reheating

Cook the soup through without adding the topping if you want to prepare it ahead of time. Put the soup in the fridge for two to three days.
You may store leftover French onion soup (with the cheesy bread topping) in the refrigerator for two to three days in an airtight container. Remember that the bread will sink and become mushy.
You may freeze French onion soup without the bread and cheese topping. For up to three months, keep in an airtight container or freezer-safe resealable bag. Let it thaw overnight in the refrigerator.
On the stovetop, reheat the soup until it is well heated. After toasting the bread, serve the soup in ovenproof bowls and garnish with cheese and the toasted bread slices. Serve after broiling.